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US 5,847,281 AGranted
System for measuring ultrasonically the elastic properties of a moving paper web
AssigneeAB Lorentzen & Wettre
InventorsRymantas J. Kazys, T. Patrick Stolpe
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Abstract
An arrangement for ultrasonically measuring the elastic properties of a moving web includes an ultrasonic wave generator and at least two ultrasonic wave detection devices which receive the generated ultrasonic wave without contacting the web. The received signal is processed such that the desired properties if the moving web can be determined.
Claims15
A system for measuring an ultrasonic wave at least partially passing through a moving paper web comprising:
- means for generating a noise type ultrasonic wave in the paper web at an excitation point;
- reference ultrasonic wave receiving means for receiving the ultrasonic wave reradiated from the paper web into the air from the excitation point, said reference ultrasonic wave receiving means being free from contact with said moving paper web;
- at least two pick-up ultrasonic wave receiving means for receiving the ultrasonic wave generated by the ultrasonic wave generating means and reradiated by the paper web, said pick-up ultrasonic wave receiving means being free from contact with said moving paper web;
- processing means to combine outputs from the pick-up ultrasonic wave receiving means such that those portions of the outputs which are dependent on velocity of the ultrasonic wave propagating in the paper web are enhanced, and those portions of the outputs which are dependent on the ultrasonic wave propagating in air are reduced at the combination of outputs;
- and
- computing means for processing the outputs from said reference ultrasonic wave receiving means and from said processing means, and determining a delay time between these outputs.
3 more elements
Dependencies are inferred from the claim text.